Pilings & fill dirt

We are building a house and need to have it on pilings, the house will be raised approx 5 ft, with 2 ft of fill dirt level with the pilings and the footings on top of that with chain wall going up the other 3 ft. Question - we have already installed the pilings and they are sticking out of the ground 2 ft, we now need to have fill dirt brought in and made level with the pilings - can that be done and can a bobcat ride on top of the pilings which are about size of telephone pole. It seems we have done the process backwards but when we asked the pilings guy, he said no, let us go ahead and put pilings first before the fill dirt?